JPH0519541Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an engine cooling system, and particularly to an engine cooling system in which at least two engine cooling systems are arranged around an engine combustion chamber.

[Conventional technology]

If the temperature of the engine combustion chamber is too high, many knocks will occur, and the efficiency of filling intake air will decrease, leading to a decrease in output. On the other hand, since the valve train in the cylinder head generates frictional heat, it is generally desirable to cool the upper side of the combustion chamber by keeping it at a relatively low temperature. On the other hand, it is generally considered desirable to cool the side portions of the combustion chamber and the lower engine cylinder side by keeping them at a high temperature. This is because frictional heat is generated on the sliding surfaces between the combustion chamber wall and the piston, and on the sliding surfaces of the crankshaft bearings, depending on the fit and oil film formation. This is because it is considered a good idea to keep the engine at a high temperature to reduce frictional resistance and suppress a drop in output.

Therefore, a system is known in which the cylinder head side and the cylinder block side are cooled separately using relatively low temperature cooling water and relatively high temperature cooling water.

[Problem that the invention attempts to solve]

However, cooling water usually begins to boil at around 100°C and generates bubbles, so even if such cooling water can be used to keep the sides of the cylinder block relatively high, there is a limit to its temperature. .

The present invention was developed to solve these problems, and by using oil, it is possible to maintain the side peripheral wall of the engine combustion chamber at a relatively high temperature and cool it. An object of the present invention is to provide an engine cooling device that can prevent a decrease in cooling capacity due to air bubbles mixed in.

[Means for solving problems]

Therefore, the engine cooling device of the present invention cools the engine combustion chamber formed by the cylinder head, the cylinder block superimposed on the cylinder head, and the piston sliding inside the engine cylinder of the cylinder block. In order to separate the head side and cylinder block side,
an upper cooling system that cools the cylinder head side;
A lower oil circulation system that cools the cylinder block side is provided separately, and the lower oil circulation system is provided with an oil jacket that is formed around the engine cylinder and holds cooling oil. An oil inlet is provided at the bottom of the engine, and in order to collect and discharge air bubbles that remain in the inlet oil jacket in one place, the inlet oil jacket has a top surface that slopes along the longitudinal direction of the engine. A bubble discharge passage is formed between the upper part of the oil jacket and the above, and discharges the bubbles guided along the inclined top surface to the oil pan connected to the lower part of the cylinder block. It is characterized by being interposed between the oil pan and the part that communicates with the oil pan.

[Effect]

In the engine cooling system of the present invention described above, the engine cylinder is cooled while being maintained at a relatively high temperature by the cooling oil in the oil jacket. In addition, since the air bubbles mixed in the cooling oil in the oil jacket are separated and discharged by the inlet oil jacket, the cooling oil that is subsequently discharged from the inlet oil jacket via the outlet oil jacket is No air bubbles are present in the flow of oil, and the cooling effect is not reduced.

〔Example〕

Below, an engine cooling system as an embodiment of the present invention will be explained with reference to the drawings. Fig. 1 is a schematic view of the oil jacket and oil gear with the cover removed, and Fig. 2 is a cross-sectional view thereof. , FIG. 3 is an exploded perspective view of its main parts, FIG. 4 is an explanatory diagram of its three-part cooling system, FIG. 5 is a schematic diagram showing a modification thereof corresponding to FIG. 1, and FIG. 2 is a schematic diagram showing another modification example corresponding to FIG. 2. FIG.

Now, this embodiment relates to a cooling system for a 4-cycle DOHC in-line 4-cylinder engine, and as shown in FIGS. 2 and 3, the main body of this engine includes a cylinder block 1 and its upper It consists of a cylinder head 2, a cylinder head upper 3 above it, a cylinder head cover 4 above it, a crank cover 5 below the cylinder block 1, and an oil pan 6.

A crankshaft 7 which is long in the longitudinal direction of the engine (perpendicular to the plane of the paper in FIG. 2) is housed in the center of the lower part of the cylinder block 1, and for this reason, a plurality of crankshafts 7 for pivotally supporting the crankshaft 7 are housed in this part. A crank bearing 8 is provided, the upper part 8a of which is integrally formed at the bottom of the cylinder block 1.

The lower portion 8b of the crank bearing 8 is integrally formed within the crank cover 5, which overlaps the upper portion 8a on the cylinder block 1 side from below. The crank cover 5 has a ladder shape consisting of left and right skirt parts 5a, 5b and lower parts 8b of a plurality of crank bearings 8 arranged in tandem between them (see Fig. 3). The peripheral portion of the cylinder block 1 is tightened by a plurality of bolts 9, and has an upper portion 8a and a lower portion 8b.
The crank bearing 8 consisting of both members is tightened with a plurality of through bolts 10, respectively.

Further, the downward opening of the crank cover 5 is closed by an oil pan 6, and an oil pump 11 for supplying lubricating oil in the oil pan 6 to various parts of the engine is housed in a part of the oil pan 6. Note that this oil pump 11 is driven by the crankshaft 7 via a chain or the like.

On the side peripheral wall of the cylinder block 1, four liner parts 13 are formed in tandem as an inner peripheral wall member that accommodates a piston 12 that slides up and down, and a separate liner part 13 is formed to cover these liner parts 13. A plate-shaped cover 14 as a formed outer peripheral wall member
A, 14B, 14C, and 14D are attached, and these liner portions 13 and covers 14A to 14D constitute an oil jacket 15 sealed therebetween. That is, as shown in FIG. 3, this liner part 13 has pillar parts 16 at the four corners, and four pillar parts 16 on the front, rear, left and right sides are connected to these four pillar parts 16 and the upper and lower flange parts 13a through packings (not shown). Plate-shaped covers 14A to 14D are bolted. In this way, the liner section 13 and the covers 14A to 14
The annular space between D and the oil jacket 15
is formed as.

In FIG. 2, a horizontal protrusion 13b long in the longitudinal direction of the engine is formed at the lower end of the liner portion 13 forming the left side peripheral wall, and the tip of this protrusion 13b comes into close contact with the inner wall surface of the cover 14A. An oil jacket 15 is formed above the protrusion 13b, and an oil gear gallery 17 is formed below the protrusion 13b. These oil jackets 15
The oil gear gallery 17 is located in the lower oil circulation system 43 (see FIG. 4), and the oil gear gallery 17 is connected to a high pressure oil passage 18 formed in the lower wall of the cylinder block 1.
It is connected to the discharge port of the oil pump 11 via an oil cleaner 19 attached to the outside of the lower part of the cylinder block 1, a high pressure oil pipe 20, etc. Also,
Projection 13b which becomes the upper wall of this oil gear rally 17
A check valve 22 as a pressure regulating means is formed at a predetermined position. It has a function as an oil inlet that allows oil to flow into the oil jacket 15 which is long in the longitudinal direction of the engine.

By the way, the oil jacket part 1 on the oil inflow side
The top surface 15A-1 of 5A is as shown in FIG.
The top surface is inclined along the longitudinal direction of the engine. In this case, the top surface above the disposed portion of the check valve 22 is the lowest, and the check valve 22
The top surface slopes upward as you move away from the area where it is installed. As a result, when oil flows into the oil jacket portion 15A through the check valve 22,
The air (bubbles) contained in this oil is collected above the oil jacket part 15A, moves obliquely upward along the top surface 15A-1 of the oil jacket part 15A, and is concentrated at the highest position. I am forced to do it.

One end of the return pipe 100 serving as a bubble discharge passage is opened at the part where the air bubbles are collected in one place through a nipple with a cover 14A, and the other end of the return pipe 100 is opened. penetrates the bottom of the cylinder block 1 and enters the crank chamber 25.
It communicates with the side. The inner diameter of the return pipe 100 is set to such a value that a required difference is created between the pressure inside the oil jacket 15 and the pressure on the crank chamber side (approximately atmospheric pressure). Of course return pipe 100
An orifice may be provided as appropriate in the middle.

As a result, the air in the oil jacket 15 is returned to the crank chamber side through the return pipe 100 along with the oil in the oil jacket 15 due to the above-mentioned differential pressure, so that it floats to the top of the oil jacket 15 and forms one spot. Most of the air bubbles collected in this area remain in this area and are removed through the return pipe 100.

Further, a vertically long return path 23 is integrally formed in a part of the cover 14B forming the outer wall of the oil jacket portion 15B shown on the right side in FIG. The return passage 23 communicates with an overflow hole 24 opening toward the upper edge of the oil jacket 15 and a return port 26 at the upper part of the crank chamber 25. In addition, crank chamber 2
A curved plate 27 is disposed below the return port 26 in the oil pump 5 so that the oil from the return port 26 can smoothly flow down to the oil pan 6 below. Therefore, the oil is supplied into the oil jacket 15 from the oil gear gallery 17 and then flows into the return pipe 100.
Subtracting the amount that is returned to the crank chamber 25 side with the air through the oil, the amount overflows from the overflow hole 24 and is returned to the oil pan 6, and a predetermined amount of oil is always maintained in the oil jacket 15 while circulating the oil. ing.

Furthermore, double annular grooves 29a and 30a are formed on the upper edge of the cylinder block 1 to annularly surround the engine combustion chamber 28 formed by the cylinder head 2, cylinder block 1, and piston 12. Of these, the inner annular groove 29a
is formed to extend downward from the upper end by an extension amount H.

On the other hand, the cylinder head 2 forming the upper peripheral wall of the combustion chamber 28 is connected to the intake port 31 of each combustion chamber 28.
is connected to the intake manifold 32, and the exhaust port 33 is connected to the exhaust manifold 34, respectively, and intake and exhaust valves 35 and 36 are housed therein. In addition, a downward annular groove 29 opening downward is provided at the lower end of the groove.
b, 30b, which oppose the double upward annular grooves 29a, 30a on the cylinder block 1 side to constitute the water jacket 29 and the water gear gallery 30 outside thereof. Note that the water jacket 29 is formed to extend upward so as to surround the intake port 31 and the exhaust port 33.

Both the water gear 30 and the water jacket 29 are in the cooling water circulation system 44 (see FIG. 3), and the water gear 30 receives the cooling water discharged from the water pump (not shown) and diverts it toward the water jacket 29. Supply evenly. That is, the water gear gallery 30 and the water jacket 29 communicate with each other through communication holes 37 having different inner diameters at a plurality of locations. Further, an outlet (not shown) is formed at a predetermined position of the water jacket 29, and the cooling water discharged from this outlet is returned to the water pump (not shown) via a cooling water pipe (not shown). It's getting old.

The cylinder head asper 3 superimposed on the upper side of the cylinder head 2 is the upper part of the cylinder head in a broad sense, and carries the intake camshaft 38, exhaust camshaft 39, intake valve spring 40, exhaust valve spring 41, etc. that make up the valve train. accommodate. Also, this cylinder head opening 3
A plurality of through holes for through bolts 10 are formed in the bottom wall of the cylinder, and these through bolts 10 integrally connect the cylinder head upper 3, the cylinder head 2, the cylinder block 1, and the crank cover 5. Here, a cylindrical guide column 102 as shown in FIG. 3 is provided at the portion of each through bolt 10 that passes through the oil jacket 15, and each through bolt 10 passes through each cylindrical guide column 102. Penetrating.

In addition, the valve train in the camshaft chamber 42 surrounded by the cylinder head upper 3 and the cylinder head cover 4 is connected to an upper oil circulation system 45 separate from the crank chamber 25 side.
(see Figure 4) and cooled. That is, an oil pump (not shown) is attached to the end of the intake camshaft 38, and operates to supply oil on the bottom wall of the camshaft chamber 42 to the sliding surfaces in the valve system.

With the above-mentioned configuration, when such an engine cooling system is operated, the upper circumferential wall of the combustion chamber 28, the cylinder head 2, and the portion of the cylinder block 1 extending downward from the upper end thereof to the extent H are covered with water jackets 29. Cooled by circulating cooling water. At the same time, the main part of the engine cylinder, which is the side peripheral wall of the combustion chamber 28 (excluding the upper end from the upper end to the extension amount H), and the crank chamber 25 side are:
Cooled by cooling oil in the lower oil circulation system 43 including the oil jacket 15 and oil pan 6,
Or be lubricated. Further, the valve train side is cooled and lubricated by oil in the upper cooling system 45.

In this way, when the engine body shown in Fig. 2 is driven, the engine cooling system, which is divided into three parts, operates independently, and by keeping the upper circumferential wall of the combustion chamber 28 at a relatively low temperature, the occurrence of knocks is suppressed. , the expansion of the intake air is suppressed to improve the filling efficiency, and the oil film is formed while keeping the sliding surfaces between the liner section 13 and the piston 12 and the crank bearing 8 at a relatively high temperature. It is possible to significantly reduce the frictional resistance of the parts and improve the output. In particular, compared to water, the oil in the oil jacket 15 can suppress the generation of bubbles even at high temperatures, and uneven cooling of the liner section 13 is less likely to occur.

Further, even if air bubbles are generated when oil is introduced into the oil jacket portion 15A and the air bubbles accumulate in the upper part of the oil jacket portion 15A, the top surface 15A-1 of the oil jacket portion 15A is As shown in Fig. 1, since it is formed to be inclined along the longitudinal direction of the engine, the air bubbles are concentrated in one place, and furthermore, the collected air bubbles are returned together with the oil in the oil jacket part 15A. Since the air bubbles are returned to the crank chamber 25 side and ultimately to the oil pan 6 side through the pipe 100, the air bubbles do not accumulate in the upper part of the oil jacket portion 15A, and it is possible to prevent the cooling performance from deteriorating due to the air bubbles. This provides sufficient cooling performance.

Further, the oil in the oil jacket 15 overflows from the overflow hole 24 at the highest position in the oil jacket 15 and returns to the oil pan 6, causing air bubbles to be generated in the oil jacket 15, for example. In addition to being effectively removed by the return pipe 100, the overflow hole 24 also allows the oil to quickly flow out from the oil jacket 15.

In addition, by maintaining a sufficient volume of the oil jacket 15, the oil pan 6 side only needs to contain the minimum necessary amount of oil. It also has the advantage of being able to reduce

In addition, an oil drain hole communicating with the oil pan 6 is provided substantially at the lower end of the oil jacket portion 15B.
This oil drain hole may be closed by a drain plug that can be opened and closed freely. In this case, when changing the oil, the oil accumulated in the oil jacket 15 can be quickly drained from the oil drain hole into the oil pan 6 by removing the drain plug. Can be discharged.

Further, in this embodiment, the top surface 15A-1 of the oil jacket portion 15A is formed to be inclined over the entire length in the longitudinal direction of the engine, as shown in FIG. As shown, the top surface may be formed such that both sides slope downward and upward along the longitudinal direction of the engine so that the central part in the longitudinal direction of the engine is the highest. In this case, the bubbles are placed in one desired location. They can be gathered together, making it easy to attach nipples, etc.

Furthermore, as shown in FIG. 6, the return pipe 100 may be a built-in type built into the cover 14A. In this case, the return pipe 100 is not visible from the outside, making it compact and aesthetically pleasing.

Further, the top surface of the water jacket 15A may be further inclined outward. In this way, air bubbles can be collected in one place while being kept away from the engine cylinder, further improving the engine cooling performance. can bring.

[Effect of idea]

As detailed above, the engine cooling device of the present invention provides the following effects and advantages.

(1) The engine combustion chamber is cooled separately on the cylinder head side and cylinder block side, so
The cooling oil in the oil jacket allows the engine cylinder to be cooled while being kept at a relatively high temperature, thereby contributing to improved output.

(2) Air bubbles mixed into the cooling oil supplied from the oil inlet provided at the bottom of the oil jacket
As the air flows, the air bubbles are smoothly discharged from the air bubble discharge passage provided at the top of the oil jacket.

(3) Since the air bubbles mixed in the cooling oil in the oil jacket are separated and discharged by the inlet oil jacket, the cooling oil is then discharged from the inlet oil jacket via the outlet oil jacket. There are no air bubbles in the flow of oil, and the cooling effect does not deteriorate.

[Brief explanation of the drawing]

The figures show an engine cooling system as an embodiment of the present invention; Fig. 1 is a schematic view of the oil jacket and oil gear with the cover removed; Fig. 2 is a sectional view thereof; Third
The figure is an exploded perspective view of the main parts, and Figure 4 is part 3.
An explanatory diagram of the divided cooling system, Fig. 5 shows the first modification.
FIG. 6 is a schematic diagram corresponding to FIG. 2, and FIG. 6 is a schematic diagram showing another modification example corresponding to FIG. 1... Cylinder block, 2... Cylinder head, 3... Cylinder head upper, 4... Cylinder head cover, 5... Crank cover, 6...
Oil pan, 7...Crankshaft, 8...Crank bearing, 8a...Top portion of crank bearing, 8b...
...Lower part of crank bearing, 9...Bolt, 10...
...Through bolt, 11...Oil pump, 12...
Piston, 13...liner part, 13a...flange part, 13b...projection, 14A-14D...cover, 15...oil jacket, 15A, 15B
... Oil jacket part, 15A-1 ... Top surface of oil jacket part, 15a ... Oil drain hole, 1
6... Pillar part, 17... Oil gear rally, 18...
High pressure oil passage, 19... Oil cleaner, 20... High pressure oil pipe, 21... Drain plug, 22... Check valve, 23... Return path, 24... Overflow hole, 25... Crank chamber, 26...
Return port, 27... Curved plate, 28... Engine combustion chamber, 29... Water jacket, 29a, 29
b...Annular groove, 30...Water gear rary, 30
a, 30b...Annular groove, 31...Intake port, 3
2...Intake manifold, 33...Exhaust port,
34...exhaust manifold, 35...intake valve, 3
6... Exhaust valve, 37... Communication hole, 38... Intake camshaft, 39... Exhaust camshaft, 40... Intake valve spring, 41... Exhaust valve spring, 42... Camshaft chamber, 4
3...Lower oil circulation system, 44...Cooling water circulation system, 4
5... Upper cooling system, 100... Return pipe as a bubble discharge passage, 102... Cylindrical guide column.

Claims (1)

[Scope of utility model registration request] Cooling of the engine combustion chamber formed by the cylinder head, the cylinder block superimposed on the cylinder head, and the piston sliding inside the engine cylinder of the cylinder block is separated between the cylinder head side and the cylinder block side. In order to achieve this, an upper cooling system that cools the cylinder head side and a lower oil circulation system that cools the cylinder block side are provided separately. The oil jacket is equipped with an oil jacket for holding oil, and an oil inlet is provided at the bottom of the oil jacket. The side oil jacket is formed with a top surface inclined along the longitudinal direction of the engine, and
A portion where a bubble discharge passage for discharging the bubbles guided along the above-mentioned slanted top surface to the oil pan side connected to the lower part of the cylinder block communicates with the upper part of the above-mentioned inlet side oil jacket and the above-mentioned oil pan. An engine cooling device characterized by being interposed between.